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In vacuum applications, the pressure sensors would have a slight difference under the same packaging conditions. Considering the cost of mass production, the manufacturers can not measure product differences for each one and give a detail characteristic curve in manual. They only give an approximate vacuum range in usual. Therefore, the purchaser needs additional calibraton costs before it can be used. The purpose here is to develop an auto measurement system which records the characteristic curve of each pressure sensor and uploads corresponding characteristic datas to cloud providing end users to download for applications. A standard pressure sensor was calibrated firstly. It was used to calibrate the vacuum degree when the device is under test (DUT). From the standard sample, a linear curve of vacuum degree was obtained as a function of voltage difference. Then, the slope and intercept of that curve were determined and used as the theoretical prediction of pressure value in DUT. The voltage unit of pressure sensor is at mV level. In order to avoid the noise interference and caused the signal distortion. The differential operational amplifier was empolyed to amplify the input signal. Then, the amplified signal was transmitted to the MT 7697 microprocessor, and instantly converted it to the digital signal. Finally, the electrical signal was restored to the original level through the program calculation. This characteric datas will be automatically uploaded to the cloud system for user reference.
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